Magnetic structure and exchange interactions of the van der Waals CrPS4 monolayer under strain: A first-principles study

Intrinsic van der Waals layered magnets have attracted much attention. Herein, we carry out a comprehensive investigation of the air-stable two-dimensional van der Waals semiconducting magnet ${\mathrm{CrPS}}_{4}$ using first-principles calculations. With the first-principles linear response method and Monte Carlo simulations, we estimate the magnetic exchange constants and magnetic transition temperatures of both bulk and monolayer ${\mathrm{CrPS}}_{4}$. We find that the main intralayer interactions of bulk ${\mathrm{CrPS}}_{4}$ are all ferromagnetic coupling, while the dominant interlayer interactions of bulk ${\mathrm{CrPS}}_{4}$ are antiferromagnetic coupling. Using the calculated magnetic exchange constants, our Monte Carlo simulations show that monolayer ${\mathrm{CrPS}}_{4}$ has Curie temperature ${T}_{C}$ = 34 K. Moreover, we study the effect of uniaxial strain of monolayer ${\mathrm{CrPS}}_{4}$, and find that a uniaxial compressive strain greater than 6% along the $b$ axis would cause the magnetic ground state to change into an up-up-down-down magnetic order along the $b$ axis.